246 lines
21 KiB
HTML
246 lines
21 KiB
HTML
<!DOCTYPE html>
|
|
<html>
|
|
<!-- Created by GNU Texinfo 7.1, https://www.gnu.org/software/texinfo/ -->
|
|
<head>
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
|
|
<!-- This manual documents Guile version 3.0.10.
|
|
|
|
Copyright (C) 1996-1997, 2000-2005, 2009-2023 Free Software Foundation,
|
|
Inc.
|
|
|
|
Copyright (C) 2021 Maxime Devos
|
|
|
|
Copyright (C) 2024 Tomas Volf
|
|
|
|
|
|
Permission is granted to copy, distribute and/or modify this document
|
|
under the terms of the GNU Free Documentation License, Version 1.3 or
|
|
any later version published by the Free Software Foundation; with no
|
|
Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A
|
|
copy of the license is included in the section entitled "GNU Free
|
|
Documentation License." -->
|
|
<title>Accessing Modules from C (Guile Reference Manual)</title>
|
|
|
|
<meta name="description" content="Accessing Modules from C (Guile Reference Manual)">
|
|
<meta name="keywords" content="Accessing Modules from C (Guile Reference Manual)">
|
|
<meta name="resource-type" content="document">
|
|
<meta name="distribution" content="global">
|
|
<meta name="Generator" content=".texi2any-real">
|
|
<meta name="viewport" content="width=device-width,initial-scale=1">
|
|
|
|
<link href="index.html" rel="start" title="Top">
|
|
<link href="Concept-Index.html" rel="index" title="Concept Index">
|
|
<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
|
|
<link href="Modules.html" rel="up" title="Modules">
|
|
<link href="provide-and-require.html" rel="next" title="provide and require">
|
|
<link href="Declarative-Modules.html" rel="prev" title="Declarative Modules">
|
|
<style type="text/css">
|
|
<!--
|
|
a.copiable-link {visibility: hidden; text-decoration: none; line-height: 0em}
|
|
div.example {margin-left: 3.2em}
|
|
span:hover a.copiable-link {visibility: visible}
|
|
strong.def-name {font-family: monospace; font-weight: bold; font-size: larger}
|
|
-->
|
|
</style>
|
|
<link rel="stylesheet" type="text/css" href="https://www.gnu.org/software/gnulib/manual.css">
|
|
|
|
|
|
</head>
|
|
|
|
<body lang="en">
|
|
<div class="subsection-level-extent" id="Accessing-Modules-from-C">
|
|
<div class="nav-panel">
|
|
<p>
|
|
Next: <a href="provide-and-require.html" accesskey="n" rel="next">provide and require</a>, Previous: <a href="Declarative-Modules.html" accesskey="p" rel="prev">Declarative Modules</a>, Up: <a href="Modules.html" accesskey="u" rel="up">Modules</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html" title="Index" rel="index">Index</a>]</p>
|
|
</div>
|
|
<hr>
|
|
<h4 class="subsection" id="Accessing-Modules-from-C-1"><span>6.18.10 Accessing Modules from C<a class="copiable-link" href="#Accessing-Modules-from-C-1"> ¶</a></span></h4>
|
|
|
|
<p>The last sections have described how modules are used in Scheme code,
|
|
which is the recommended way of creating and accessing modules. You
|
|
can also work with modules from C, but it is more cumbersome.
|
|
</p>
|
|
<p>The following procedures are available.
|
|
</p>
|
|
<dl class="first-deftypefn">
|
|
<dt class="deftypefn" id="index-scm_005fc_005fcall_005fwith_005fcurrent_005fmodule"><span class="category-def">C Function: </span><span><code class="def-type">SCM</code> <strong class="def-name">scm_c_call_with_current_module</strong> <code class="def-code-arguments">(SCM <var class="var">module</var>, SCM (*<var class="var">func</var>)(void *), void *<var class="var">data</var>)</code><a class="copiable-link" href="#index-scm_005fc_005fcall_005fwith_005fcurrent_005fmodule"> ¶</a></span></dt>
|
|
<dd><p>Call <var class="var">func</var> and make <var class="var">module</var> the current module during the
|
|
call. The argument <var class="var">data</var> is passed to <var class="var">func</var>. The return
|
|
value of <code class="code">scm_c_call_with_current_module</code> is the return value of
|
|
<var class="var">func</var>.
|
|
</p></dd></dl>
|
|
|
|
<dl class="first-deftypefn">
|
|
<dt class="deftypefn" id="index-scm_005fpublic_005fvariable"><span class="category-def">C Function: </span><span><code class="def-type">SCM</code> <strong class="def-name">scm_public_variable</strong> <code class="def-code-arguments">(SCM <var class="var">module_name</var>, SCM <var class="var">name</var>)</code><a class="copiable-link" href="#index-scm_005fpublic_005fvariable"> ¶</a></span></dt>
|
|
<dt class="deftypefnx def-cmd-deftypefn" id="index-scm_005fc_005fpublic_005fvariable"><span class="category-def">C Function: </span><span><code class="def-type">SCM</code> <strong class="def-name">scm_c_public_variable</strong> <code class="def-code-arguments">(const char *<var class="var">module_name</var>, const char *<var class="var">name</var>)</code><a class="copiable-link" href="#index-scm_005fc_005fpublic_005fvariable"> ¶</a></span></dt>
|
|
<dd><p>Find a the variable bound to the symbol <var class="var">name</var> in the public
|
|
interface of the module named <var class="var">module_name</var>.
|
|
</p>
|
|
<p><var class="var">module_name</var> should be a list of symbols, when represented as a
|
|
Scheme object, or a space-separated string, in the <code class="code">const char *</code>
|
|
case. See <code class="code">scm_c_define_module</code> below, for more examples.
|
|
</p>
|
|
<p>Signals an error if no module was found with the given name. If
|
|
<var class="var">name</var> is not bound in the module, just returns <code class="code">#f</code>.
|
|
</p></dd></dl>
|
|
|
|
<dl class="first-deftypefn">
|
|
<dt class="deftypefn" id="index-scm_005fprivate_005fvariable"><span class="category-def">C Function: </span><span><code class="def-type">SCM</code> <strong class="def-name">scm_private_variable</strong> <code class="def-code-arguments">(SCM <var class="var">module_name</var>, SCM <var class="var">name</var>)</code><a class="copiable-link" href="#index-scm_005fprivate_005fvariable"> ¶</a></span></dt>
|
|
<dt class="deftypefnx def-cmd-deftypefn" id="index-scm_005fc_005fprivate_005fvariable"><span class="category-def">C Function: </span><span><code class="def-type">SCM</code> <strong class="def-name">scm_c_private_variable</strong> <code class="def-code-arguments">(const char *<var class="var">module_name</var>, const char *<var class="var">name</var>)</code><a class="copiable-link" href="#index-scm_005fc_005fprivate_005fvariable"> ¶</a></span></dt>
|
|
<dd><p>Like <code class="code">scm_public_variable</code>, but looks in the internals of the
|
|
module named <var class="var">module_name</var> instead of the public interface.
|
|
Logically, these procedures should only be called on modules you write.
|
|
</p></dd></dl>
|
|
|
|
<dl class="first-deftypefn">
|
|
<dt class="deftypefn" id="index-scm_005fpublic_005flookup"><span class="category-def">C Function: </span><span><code class="def-type">SCM</code> <strong class="def-name">scm_public_lookup</strong> <code class="def-code-arguments">(SCM <var class="var">module_name</var>, SCM <var class="var">name</var>)</code><a class="copiable-link" href="#index-scm_005fpublic_005flookup"> ¶</a></span></dt>
|
|
<dt class="deftypefnx def-cmd-deftypefn" id="index-scm_005fc_005fpublic_005flookup"><span class="category-def">C Function: </span><span><code class="def-type">SCM</code> <strong class="def-name">scm_c_public_lookup</strong> <code class="def-code-arguments">(const char *<var class="var">module_name</var>, const char *<var class="var">name</var>)</code><a class="copiable-link" href="#index-scm_005fc_005fpublic_005flookup"> ¶</a></span></dt>
|
|
<dt class="deftypefnx def-cmd-deftypefn" id="index-scm_005fprivate_005flookup"><span class="category-def">C Function: </span><span><code class="def-type">SCM</code> <strong class="def-name">scm_private_lookup</strong> <code class="def-code-arguments">(SCM <var class="var">module_name</var>, SCM <var class="var">name</var>)</code><a class="copiable-link" href="#index-scm_005fprivate_005flookup"> ¶</a></span></dt>
|
|
<dt class="deftypefnx def-cmd-deftypefn" id="index-scm_005fc_005fprivate_005flookup"><span class="category-def">C Function: </span><span><code class="def-type">SCM</code> <strong class="def-name">scm_c_private_lookup</strong> <code class="def-code-arguments">(const char *<var class="var">module_name</var>, const char *<var class="var">name</var>)</code><a class="copiable-link" href="#index-scm_005fc_005fprivate_005flookup"> ¶</a></span></dt>
|
|
<dd><p>Like <code class="code">scm_public_variable</code> or <code class="code">scm_private_variable</code>, but if
|
|
the <var class="var">name</var> is not bound in the module, signals an error. Returns a
|
|
variable, always.
|
|
</p>
|
|
<div class="example">
|
|
<pre class="example-preformatted">static SCM eval_string_var;
|
|
|
|
/* NOTE: It is important that the call to 'my_init'
|
|
happens-before all calls to 'my_eval_string'. */
|
|
void my_init (void)
|
|
{
|
|
eval_string_var = scm_c_public_lookup ("ice-9 eval-string",
|
|
"eval-string");
|
|
}
|
|
|
|
SCM my_eval_string (SCM str)
|
|
{
|
|
return scm_call_1 (scm_variable_ref (eval_string_var), str);
|
|
}
|
|
</pre></div>
|
|
</dd></dl>
|
|
|
|
<dl class="first-deftypefn">
|
|
<dt class="deftypefn" id="index-scm_005fpublic_005fref"><span class="category-def">C Function: </span><span><code class="def-type">SCM</code> <strong class="def-name">scm_public_ref</strong> <code class="def-code-arguments">(SCM <var class="var">module_name</var>, SCM <var class="var">name</var>)</code><a class="copiable-link" href="#index-scm_005fpublic_005fref"> ¶</a></span></dt>
|
|
<dt class="deftypefnx def-cmd-deftypefn" id="index-scm_005fc_005fpublic_005fref"><span class="category-def">C Function: </span><span><code class="def-type">SCM</code> <strong class="def-name">scm_c_public_ref</strong> <code class="def-code-arguments">(const char *<var class="var">module_name</var>, const char *<var class="var">name</var>)</code><a class="copiable-link" href="#index-scm_005fc_005fpublic_005fref"> ¶</a></span></dt>
|
|
<dt class="deftypefnx def-cmd-deftypefn" id="index-scm_005fprivate_005fref"><span class="category-def">C Function: </span><span><code class="def-type">SCM</code> <strong class="def-name">scm_private_ref</strong> <code class="def-code-arguments">(SCM <var class="var">module_name</var>, SCM <var class="var">name</var>)</code><a class="copiable-link" href="#index-scm_005fprivate_005fref"> ¶</a></span></dt>
|
|
<dt class="deftypefnx def-cmd-deftypefn" id="index-scm_005fc_005fprivate_005fref"><span class="category-def">C Function: </span><span><code class="def-type">SCM</code> <strong class="def-name">scm_c_private_ref</strong> <code class="def-code-arguments">(const char *<var class="var">module_name</var>, const char *<var class="var">name</var>)</code><a class="copiable-link" href="#index-scm_005fc_005fprivate_005fref"> ¶</a></span></dt>
|
|
<dd><p>Like <code class="code">scm_public_lookup</code> or <code class="code">scm_private_lookup</code>, but
|
|
additionally dereferences the variable. If the variable object is
|
|
unbound, signals an error. Returns the value bound to <var class="var">name</var> in
|
|
<var class="var">module_name</var>.
|
|
</p></dd></dl>
|
|
|
|
<p>In addition, there are a number of other lookup-related procedures. We
|
|
suggest that you use the <code class="code">scm_public_</code> and <code class="code">scm_private_</code>
|
|
family of procedures instead, if possible.
|
|
</p>
|
|
<dl class="first-deftypefn">
|
|
<dt class="deftypefn" id="index-scm_005fc_005flookup"><span class="category-def">C Function: </span><span><code class="def-type">SCM</code> <strong class="def-name">scm_c_lookup</strong> <code class="def-code-arguments">(const char *<var class="var">name</var>)</code><a class="copiable-link" href="#index-scm_005fc_005flookup"> ¶</a></span></dt>
|
|
<dd><p>Return the variable bound to the symbol indicated by <var class="var">name</var> in the
|
|
current module. If there is no such binding or the symbol is not
|
|
bound to a variable, signal an error.
|
|
</p></dd></dl>
|
|
|
|
<dl class="first-deftypefn">
|
|
<dt class="deftypefn" id="index-scm_005flookup"><span class="category-def">C Function: </span><span><code class="def-type">SCM</code> <strong class="def-name">scm_lookup</strong> <code class="def-code-arguments">(SCM <var class="var">name</var>)</code><a class="copiable-link" href="#index-scm_005flookup"> ¶</a></span></dt>
|
|
<dd><p>Like <code class="code">scm_c_lookup</code>, but the symbol is specified directly.
|
|
</p></dd></dl>
|
|
|
|
<dl class="first-deftypefn">
|
|
<dt class="deftypefn" id="index-scm_005fc_005fmodule_005flookup"><span class="category-def">C Function: </span><span><code class="def-type">SCM</code> <strong class="def-name">scm_c_module_lookup</strong> <code class="def-code-arguments">(SCM <var class="var">module</var>, const char *<var class="var">name</var>)</code><a class="copiable-link" href="#index-scm_005fc_005fmodule_005flookup"> ¶</a></span></dt>
|
|
<dt class="deftypefnx def-cmd-deftypefn" id="index-scm_005fmodule_005flookup"><span class="category-def">C Function: </span><span><code class="def-type">SCM</code> <strong class="def-name">scm_module_lookup</strong> <code class="def-code-arguments">(SCM <var class="var">module</var>, SCM <var class="var">name</var>)</code><a class="copiable-link" href="#index-scm_005fmodule_005flookup"> ¶</a></span></dt>
|
|
<dd><p>Like <code class="code">scm_c_lookup</code> and <code class="code">scm_lookup</code>, but the specified
|
|
module is used instead of the current one.
|
|
</p></dd></dl>
|
|
|
|
<dl class="first-deftypefn">
|
|
<dt class="deftypefn" id="index-scm_005fmodule_005fvariable"><span class="category-def">C Function: </span><span><code class="def-type">SCM</code> <strong class="def-name">scm_module_variable</strong> <code class="def-code-arguments">(SCM <var class="var">module</var>, SCM <var class="var">name</var>)</code><a class="copiable-link" href="#index-scm_005fmodule_005fvariable"> ¶</a></span></dt>
|
|
<dd><p>Like <code class="code">scm_module_lookup</code>, but if the binding does not exist, just
|
|
returns <code class="code">#f</code> instead of raising an error.
|
|
</p></dd></dl>
|
|
|
|
<p>To define a value, use <code class="code">scm_define</code>:
|
|
</p>
|
|
<dl class="first-deftypefn">
|
|
<dt class="deftypefn" id="index-scm_005fc_005fdefine-1"><span class="category-def">C Function: </span><span><code class="def-type">SCM</code> <strong class="def-name">scm_c_define</strong> <code class="def-code-arguments">(const char *<var class="var">name</var>, SCM <var class="var">val</var>)</code><a class="copiable-link" href="#index-scm_005fc_005fdefine-1"> ¶</a></span></dt>
|
|
<dd><p>Bind the symbol indicated by <var class="var">name</var> to a variable in the current
|
|
module and set that variable to <var class="var">val</var>. When <var class="var">name</var> is already
|
|
bound to a variable, use that. Else create a new variable.
|
|
</p></dd></dl>
|
|
|
|
<dl class="first-deftypefn">
|
|
<dt class="deftypefn" id="index-scm_005fdefine-1"><span class="category-def">C Function: </span><span><code class="def-type">SCM</code> <strong class="def-name">scm_define</strong> <code class="def-code-arguments">(SCM <var class="var">name</var>, SCM <var class="var">val</var>)</code><a class="copiable-link" href="#index-scm_005fdefine-1"> ¶</a></span></dt>
|
|
<dd><p>Like <code class="code">scm_c_define</code>, but the symbol is specified directly.
|
|
</p></dd></dl>
|
|
|
|
<dl class="first-deftypefn">
|
|
<dt class="deftypefn" id="index-scm_005fc_005fmodule_005fdefine"><span class="category-def">C Function: </span><span><code class="def-type">SCM</code> <strong class="def-name">scm_c_module_define</strong> <code class="def-code-arguments">(SCM <var class="var">module</var>, const char *<var class="var">name</var>, SCM <var class="var">val</var>)</code><a class="copiable-link" href="#index-scm_005fc_005fmodule_005fdefine"> ¶</a></span></dt>
|
|
<dt class="deftypefnx def-cmd-deftypefn" id="index-scm_005fmodule_005fdefine"><span class="category-def">C Function: </span><span><code class="def-type">SCM</code> <strong class="def-name">scm_module_define</strong> <code class="def-code-arguments">(SCM <var class="var">module</var>, SCM <var class="var">name</var>, SCM <var class="var">val</var>)</code><a class="copiable-link" href="#index-scm_005fmodule_005fdefine"> ¶</a></span></dt>
|
|
<dd><p>Like <code class="code">scm_c_define</code> and <code class="code">scm_define</code>, but the specified
|
|
module is used instead of the current one.
|
|
</p></dd></dl>
|
|
|
|
<p>In some rare cases, you may need to access the variable that
|
|
<code class="code">scm_module_define</code> would have accessed, without changing the
|
|
binding of the existing variable, if one is present. In that case, use
|
|
<code class="code">scm_module_ensure_local_variable</code>:
|
|
</p>
|
|
<dl class="first-deftypefn">
|
|
<dt class="deftypefn" id="index-scm_005fmodule_005fensure_005flocal_005fvariable"><span class="category-def">C Function: </span><span><code class="def-type">SCM</code> <strong class="def-name">scm_module_ensure_local_variable</strong> <code class="def-code-arguments">(SCM <var class="var">module</var>, SCM <var class="var">sym</var>)</code><a class="copiable-link" href="#index-scm_005fmodule_005fensure_005flocal_005fvariable"> ¶</a></span></dt>
|
|
<dd><p>Like <code class="code">scm_module_define</code>, but if the <var class="var">sym</var> is already locally
|
|
bound in that module, the variable’s existing binding is not reset.
|
|
Returns a variable.
|
|
</p></dd></dl>
|
|
|
|
<dl class="first-deftypefn">
|
|
<dt class="deftypefn" id="index-scm_005fmodule_005freverse_005flookup"><span class="category-def">C Function: </span><span><code class="def-type">SCM</code> <strong class="def-name">scm_module_reverse_lookup</strong> <code class="def-code-arguments">(SCM <var class="var">module</var>, SCM <var class="var">variable</var>)</code><a class="copiable-link" href="#index-scm_005fmodule_005freverse_005flookup"> ¶</a></span></dt>
|
|
<dd><p>Find the symbol that is bound to <var class="var">variable</var> in <var class="var">module</var>. When no such binding is found, return <code class="code">#f</code>.
|
|
</p></dd></dl>
|
|
|
|
<dl class="first-deftypefn">
|
|
<dt class="deftypefn" id="index-scm_005fc_005fdefine_005fmodule"><span class="category-def">C Function: </span><span><code class="def-type">SCM</code> <strong class="def-name">scm_c_define_module</strong> <code class="def-code-arguments">(const char *<var class="var">name</var>, void (*<var class="var">init</var>)(void *), void *<var class="var">data</var>)</code><a class="copiable-link" href="#index-scm_005fc_005fdefine_005fmodule"> ¶</a></span></dt>
|
|
<dd><p>Define a new module named <var class="var">name</var> and make it current while
|
|
<var class="var">init</var> is called, passing it <var class="var">data</var>. Return the module.
|
|
</p>
|
|
<p>The parameter <var class="var">name</var> is a string with the symbols that make up
|
|
the module name, separated by spaces. For example, ‘<samp class="samp">"foo bar"</samp>’ names
|
|
the module ‘<samp class="samp">(foo bar)</samp>’.
|
|
</p>
|
|
<p>When there already exists a module named <var class="var">name</var>, it is used
|
|
unchanged, otherwise, an empty module is created.
|
|
</p></dd></dl>
|
|
|
|
<dl class="first-deftypefn">
|
|
<dt class="deftypefn" id="index-scm_005fc_005fresolve_005fmodule"><span class="category-def">C Function: </span><span><code class="def-type">SCM</code> <strong class="def-name">scm_c_resolve_module</strong> <code class="def-code-arguments">(const char *<var class="var">name</var>)</code><a class="copiable-link" href="#index-scm_005fc_005fresolve_005fmodule"> ¶</a></span></dt>
|
|
<dd><p>Find the module name <var class="var">name</var> and return it. When it has not
|
|
already been defined, try to auto-load it. When it can’t be found
|
|
that way either, create an empty module. The name is interpreted as
|
|
for <code class="code">scm_c_define_module</code>.
|
|
</p></dd></dl>
|
|
|
|
<dl class="first-deftypefn">
|
|
<dt class="deftypefn" id="index-scm_005fc_005fuse_005fmodule"><span class="category-def">C Function: </span><span><code class="def-type">SCM</code> <strong class="def-name">scm_c_use_module</strong> <code class="def-code-arguments">(const char *<var class="var">name</var>)</code><a class="copiable-link" href="#index-scm_005fc_005fuse_005fmodule"> ¶</a></span></dt>
|
|
<dd><p>Add the module named <var class="var">name</var> to the uses list of the current
|
|
module, as with <code class="code">(use-modules <var class="var">name</var>)</code>. The name is
|
|
interpreted as for <code class="code">scm_c_define_module</code>.
|
|
</p></dd></dl>
|
|
|
|
<dl class="first-deftypefn">
|
|
<dt class="deftypefn" id="index-scm_005fc_005fexport"><span class="category-def">C Function: </span><span><code class="def-type">void</code> <strong class="def-name">scm_c_export</strong> <code class="def-code-arguments">(const char *<var class="var">name</var>, ...)</code><a class="copiable-link" href="#index-scm_005fc_005fexport"> ¶</a></span></dt>
|
|
<dd><p>Add the bindings designated by <var class="var">name</var>, ... to the public interface
|
|
of the current module. The list of names is terminated by
|
|
<code class="code">NULL</code>.
|
|
</p></dd></dl>
|
|
|
|
|
|
</div>
|
|
<hr>
|
|
<div class="nav-panel">
|
|
<p>
|
|
Next: <a href="provide-and-require.html">provide and require</a>, Previous: <a href="Declarative-Modules.html">Declarative Modules</a>, Up: <a href="Modules.html">Modules</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html" title="Index" rel="index">Index</a>]</p>
|
|
</div>
|
|
|
|
|
|
|
|
</body>
|
|
</html>
|